Using historical records of rainfall and computer models that simulate climate, the researchers, including several from the National Oceanic and Atmospheric Administration, found that global warming increased the chances of such intense rains in the region by at least 40 percent.

“But it’s probably much closer to a doubling of the probability” of such an event, or a 100 percent increase, said Heidi Cullen, chief scientist for Climate Central, the research organization that coordinated the study. “Climate change played a very clear and quantifiable role,” she added.

A storm carrying large amounts of moisture from the Gulf of Mexico stalled over southern Louisiana in mid-August, bringing several days of apocalyptic rain — up to two feet in 48 hours — that caused record flooding in Baton Rouge and elsewhere. The authorities said 13 people were killed and about 55,000 homes and 6,000 businesses were damaged in what is now considered the nation’s worst natural disaster since Hurricane Sandy, the storm that hit the Northeast in 2012.

Gov. John Bel Edwards, who was forced to flee the flooding with his family, said damage was expected to be close to $9 billion.

Climate scientists have long said that a warming atmosphere and oceans should lead to more intense and frequent rainstorms, because there will be greater evaporation, and warmer air holds more moisture. But until recent years most scientists have said it was not possible to link any single event to climate change.

That is changing with the development of attribution studies, which use statistical analysis and climate modeling to compare the likelihood of an event occurring before industrialization, when there were essentially no greenhouse-gas emissions, and now, when the world is putting tens of billions of tons of carbon dioxide into the air each year.

Normally such studies can take months, largely because of the computer time required to run climate simulations. But the Louisiana study is the latest “rapid-response” research intended to determine the effect, if any, of climate change as close to the event as possible, to help inform policy makers and the public.

To speed the research, World Weather Attribution, the loose-knit research team that conducted this study, used models that have already been run. They were developed by NOAA scientists at the Geophysical Fluid Dynamics Laboratory in Princeton, N.J., and are sophisticated enough to capture the many different elements that contribute to weather in the Gulf Coast region, said Karin van der Wiel, a research associate at the laboratory.

“Hurricanes, frontal systems, thunderstorms — there are so many different ways to get a lot of precipitation” in the region, Dr. van der Wiel said. “It’s very important that the models realistically represent the weather.”

World Weather Attribution has conducted several similar studies in the past two years, including one earlier this year that linked floods in France in April to climate change. But the Louisiana study was the most difficult one yet because of the many factors involved for the Gulf Coast, said Geert Jan van Oldenborgh, a member of the team from the Royal Netherlands Meteorological Institute.

This was the first time that NOAA has participated in a rapid attribution study. Monica Allen, a NOAA spokeswoman, said the agency would consider taking part in future studies. “Researchers, communities and businesses alike see the value in these analyses,” she said. “They help us grapple with what has happened and strengthen our ability to stay resilient to future events.”

Barry D. Keim, Louisiana’s state climatologist and a professor at Louisiana State University, said that while he was not familiar with World Weather Attribution’s methods, “I’m just not convinced that we can attribute any single event to climate change.” Nonetheless, he said, “there are some general consistencies between this event and climate change.”

A version of this article appears in print on , on Page A19 of the New York edition with the headline: Climate Scientists Forecast More Floods Like Louisiana’s. Order Reprints | Today’s Paper | Subscribe